22 lines
889 B
Text
22 lines
889 B
Text
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--- Copyright (c) 2014 Microsoft Corporation. All rights reserved.
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--- Released under Apache 2.0 license as described in the file LICENSE.
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--- Author: Jeremy Avigad
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open nat
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-- first define a class of homogeneous equality
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inductive [class] simplifies_to {T : Type} (t1 t2 : T) : Prop
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| mk : t1 = t2 → simplifies_to
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namespace simplifies_to
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theorem get_eq {T : Type} {t1 t2 : T} (C : simplifies_to t1 t2) : t1 = t2 :=
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simplifies_to.rec (λx, x) C
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attribute [instance]
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theorem simp_app (S : Type) (T : Type) (f1 f2 : S → T) (s1 s2 : S)
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[C1 : simplifies_to f1 f2] [C2 : simplifies_to s1 s2] : simplifies_to (f1 s1) (f2 s2) :=
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mk (congr (get_eq C1) (get_eq C2))
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end simplifies_to
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